Method and apparatus for providing power to a marine vessel

ABSTRACT

A system and a method for providing power to a marine vessel and, more particularly to a tugboat is disclosed. The system includes diesel engines and generators and batteries which can be charged using power supplied by the generators, shore power or regenerated power. The tugboat is operated utilizing battery power only and the generators are used to provide additional power if needed or to recharge the batteries.

RELATED PRIORITY DATE APPLICATION

This application claims the benefit under 35 U.S.C. 119(e) of the U.S.provisional application No. 61/004,397 filed on Nov. 25, 2007.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to marine transportation and, moreparticularly, to a system for providing power to a marine vessel. Stillmore particularly, the present invention discloses a method andapparatus wherein, depending on the mode of operation, a combination ofbatteries and engines provide power to a marine vessel such as a tugboator a ferry boat.

BACKGROUND OF THE INVENTION

Marine vessels and, more particularly, tugboats and ferry boats are wellknown. A tugboat, or tug, is a boat used to maneuver, primarily bytowing or pushing, other marine vessels in harbors, over the open sea orthrough rivers and canals. They are also used to tow barges, disabledships, or other equipment like tow boats. Further, they are used toextinguish fires in water locations where land equipment cannot performfire fighting operations.

Presently, tugboats are powered by diesel engines. One disadvantage ofdiesel engines is that they emit a large amount of pollutants and, moreparticularly, compounds that contain carbon such as carbon dioxide.Another disadvantage is that they consume a large amount of fuel whileperforming routine tag boat operations. Another disadvantage is that theuse of diesel engines requires a large space for the drive lines in thetugboat. Still another disadvantage is that diesel engines are verynoisy and contribute to elevated levels of noise pollution.

According to the present invention, a drive system for a tugboat isprovided utilizing a combination of stored energy batteries and dieselpowered generators. The diesel generators are only used in the towingmode, that is when the tugboat is attached to a vessel, fire fightingmode or when charging the batteries.

The use of stored energy batteries dramatically reduces carbon emissionwhile meeting or exceeding the functionality, safety and powerrequirements of present day tugs. Such reduction can be as high as 90percent when compared to the present power drive designs. Further theuse of stored energy batteries substantially reduces power consumption,the drive line space requirements and the noise level.

These and other advantages and objects of the present invention willbecome apparent from the following description.

SUMMARY OF THE INVENTION

According to the present invention, a drive system for powering atugboat comprises a port section and a starboard section which issimilar to the port section. The port section and the starboard sectionmay be operated independently or may be cross connected at severalpoints, as needed. Components of the port section are similar to thecomponents of the starboard section.

The port section and the starboard section each includes a diesel engineand generator, an AC bus, a rectifier, a battery bank, a DC bus andinverters that drive the motors in the tugboat, a shore power connectionand a fire pump motor. The AC bus is connected to the generator and theshore power connection to receive electrical power therefrom. The firepump motor is connected to receive electrical power directly from thegenerator when activated. It can also receive power from a shore powersource.

The generator provides a variable voltage that can range from 10% underto 10% over rated voltage and is normally connected to the rectifier.The rectifier convert alternating current from the AC bus to directcurrent which is supplied to the DC bus.

The DC voltage from the rectifiers is used by the battery bank forrecharging and by the inverters to drive the motors loads. The batterybank is bi-directionally connected to the DC bus to receive chargingcurrent from the generator and other sources and to provide power to theDC bus 40A which in turn powers the DC to AC inverters.

The inverters are capable of handling regenerated power which isregenerated under certain conditions primarily by the winch when a loadis dropping and by the thruster when rotation is reversed or energy isharvested from the vessel hull when it slows down. Smaller amounts ofpower may also be regenerated from the steering gear or from the use ofthe thruster in harvesting power from the current. The batteries in thebattery bank are connected to automatically absorb regenerated power,either by displacing load current or by discharging. If the voltage inthe DC bus reaches a certain level, namely, about 750 volts (as adjustedfor battery temperature) a chopper diverts the excess regenerated powerto an air cooled grid resistor. Shore power available from the AC buscan also be used to charge the batteries of the battery bank through aninverter. A redundant control system is provided for each port andstarboard section.

The drive system is designed to operate in three different modes,namely, the green mode, the tow mode and the firefighting mode. Greenmode is the default mode of operation. In the green mode the vessel issupplied power only by the batteries in the battery banks withoututilizing the diesel engines for ship propulsion and/or ship service.The control system energizes the diesel engines and generators only whenneeded to provide peak power or battery charging. The batteries in thebattery banks hold enough energy to sustain 300 Hp of incidental loadsfor over 8 hours between charges; however battery life is increased ifmore shallow discharge cycles are used. The generators come on lineautomatically based on a combination of the load and the battery stateof charge. In the green mode, the minimal use of diesel engines causesubstantial reduction in noise level, energy consumption and carbonemissions. Green mode is designed for operating the tugboat betweenlocations when it is not towing another vessel and for docksideoperations.

The tow mode may be manually selected by the operator. Selecting towmode energizes the diesel engines and generators so that they will beavailable immediately to support peak power demands. The voltage fromthe generators maintains a float charge on the battery banks except atvery heavy loads, where power is drawn from the battery banks tosupplement the generators.

The fire fighting mode may be manually selected by the operator.Firefighting mode energizes both diesel engines and generators and givespriority to the fire pumps that are driven by the fire pump motors.

The use of the combination of battery banks and generators allows forreduction of use of generators in certain operating modes and, moreparticularly, in the green mode. Generators are only used in the towingmode, fire fighting mode or when charging the batteries. As a result,fuel consumption is reduced thereby reducing fuel costs and carbonemissions from the vessel. The replacement of diesel engines andgenerators with battery banks reduces the size of the drive line and theoverall space required for it.

Identical interchangeable modules are used in the inverters. They areautomatically reprogrammed and they can be replaced at sea quicklythereby reducing down time and maintenance costs.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of the preferred embodiment of the apparatusof the present invention, reference will now be made to the accompanyingdrawings, wherein:

FIG. 1 is a schematic illustrating the major functional systems of thedrive system of the present invention;

FIG. 2 is a more detailed schematic of the functional systems shown inFIG. 1; and

FIG. 3 is a schematic illustrating the controls of the drive system ofFIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1 there is shown a drive system 10 that is acomprised of a port (left) section and a starboard (right) section whichmay be operated independently or may be cross connected at severalpoints, as needed. Components of the port section are similar to thecomponents of the starboard section and similar components aredesignated by the same numeral followed by the letter “A” for thecomponents of the port section and letter “B” for the components of thestarboard section.

Accordingly, drive system 10 includes shore power connections 15A and15B, generators 20A and 20B being driven by diesel engines 10A and 10B(not shown in FIG. 1 but shown in FIG. 2), respectively, an AC bus 18comprising an AC bus 18A and an AC bus 18B interconnected through acircuit breaker 19 (1600 AF), rectifiers 25A and 25B, battery banks 30Aand 30B, a DC Bus 40 comprising a DC bus 40A and a DC bus 40Binterconnected via a switch 42(3150 DC), inverters 50A and 50B, 52, 54Aand 54B, 56A and 56B, motor control centers 60A and 60B, winch motor 62,steering motors 64A and 64B, thruster motors 66A and 66B, choppers 58Aand 58B, grid resistors 68A and 68B, and fire pump motors 72A and 72B.

AC bus 18A is connected to generator 20A and shore power connection 15Ato receive electrical power therefrom. AC bus 18B is connected togenerator 20B and shore power connection 15B to receive electrical powertherefrom. Connections are provided as shown for generators 20A and 20BAto be connected to each other or to shore power connections 15A and 15B.A circuit breaker 76A (600 AF) and a circuit breaker 78A (3200 AF) areprovided between AC bus 18A and shore power connection 15A and AC bus18A and generator 20A, respectively. Similarly, a circuit breaker 76B(600 AF) and a circuit breaker 78B (3200 AF) are provided between AC bus18B and shore power connection 15B and AC bus 18B and generator 20B,respectively.

Fire pump motors 72A and 72B are connected to receive electrical powerdirectly from generators 20A and 20B, respectively, via AC bus 18A andAC bus 18B, respectively, when activated. Circuit breakers 82A and 82B(1600 AF each) are provided before fire pump motors 72A and 72B,respectively. Shore power connections 15A and 15B can also be connectedto AC bus 18A and AC bus 18B, respectively, at the generator outputs sothat shore power can run fire pump motors 72A and 72B.

Generators 20A and 20B provide 460-690 VAC, 45-60 Hz power and arenormally connected individually to rectifiers 25A and 25B, respectively,when generators 20A and 20B are active. Generators 20A and 20B may beconnected to each other or shore power, if synchronized. Rectifiers 25Aand 25B convert alternating current (“AC”) from AC bus 18A and AC bus18B, respectively, to direct current (“DC”) which is supplied to DC bus40A and DC bus 40B, respectively. Circuit breakers 84A and 84B (3200 AFeach) are provided before rectifiers 25A and 25B, respectively.

The DC voltage from the rectifiers is used by batteries and motor loads,as described hereinafter. The DC voltage in DC bus 40A and DC bus 40B isdetermined by the batteries in battery bank 30A and 30B and their rateof charge or discharge. The rate of charge may be controlled byadjusting the output voltage of generators 20A and 20B.

Battery bank 30A is bi-directionally connected to DC bus 40A to receivecharging current from generator 20A and other sources as hereinafterdescribed and to provide power to DC bus 40A which in turn powers DC toAC inverters 50A, 52, 54A, and 56A that drive motor control center 60A,winch motor 62, steering motor 64A and thruster motor 66A, respectively.DC bus 40A is also connected to a chopper 58A that is coupled with agrid resistor 68A.

Inverters 50A, 52, 54A and 56A are capable of handling 100% regeneratedpower. Such power is regenerated under certain conditions primarily bythe winch when a load is dropping and the thruster when rotation isreversed. Smaller amounts of power may also be regenerated from thesteering gear or from the use of the thruster in harvesting power fromthe current. The batteries in battery bank 30A are connected toautomatically absorb regenerated power, either by displacing loadcurrent or by discharging. If the voltage in the DC bus 40A reaches acertain level, namely, about 750 volts (as adjusted for batterytemperature) chopper 58A diverts the excess regenerated power to aircooled grid resistor 68A.

Battery bank 30B is bi-directionally connected to DC bus 40B to receivecharging current from generator 20B and other sources as hereinafterdescribed and to provide power to DC bus 40B which in turn powers DC toAC inverters 50B, 54B, and 56B that drive motor control center 60B,steering motor 64B and thruster motor 66B, respectively. DC bus 40B isalso connected to a chopper 58B coupled with a grid resistor 68B.

Inverters 50B, 54B and 56B are capable of handling the regenerated powerfrom their corresponding loads and, more particularly, the steering gearand the thruster of the starboard section. The batteries of battery bank30B automatically absorb the regenerated power and any overloads aredirected by chopper 58B to grid resistor 68B.

Normally, DC bus 40A is supplied by battery bank 30A and DC bus 40B issupplied by battery bank 30B. DC bus 40A and DC bus 40B may be connectedso that, in the event one of battery banks 30A or 30B requires serviceor is offline, bus tie manual contactors are provided to cross feed thepower from battery bank 30A to DC bus 40B or from battery bank 30B to DCbus 40A. The contactors are manually operated and have the ability to beelectrically interlocked. They include auxiliary contacts to providetheir status information to the overall operating system.

When operating with power provided only by the batteries, each of bus DC40A and DC bus 40B is fed from its corresponding battery bank, namely,battery bank 30A and battery bank 30B, respectively. The current limitsof the AC drives are limited based upon the monitored output current ofthe online battery bank. The DC current output is monitored by means of5000 ADC rated Hal Effect Devices (“HEDs”). Set points are programmedinto the operating software to prevent battery depletion beyond presetlevels. In the event of either DC bus 40A or DC bus 40B fails, the otherbus is still online due to the split DC bus system.

Motor control center 60A is also connected directly to AC bus 18A todraw power directly from shore power connection 15A or from generator20A bypassing the batteries and electronics, if needed. Similarly, motorcontrol center 60B is connected directly to AC bus 18B to draw powerdirectly from shore power connection 15B or from generator 20B bypassingthe batteries and electronics, if needed. Shore power is normallyconnected via shore power connections 15A and 15B to motor controlcenters 60A and 60B so that their loads can be operated directly, evenif the batteries and inverters are out of service.

Shore power available from AC bus 18A and AC bus 18B can also be used tocharge batteries of battery banks 30A and 30B, respectively, throughinverters 50A and 50B, respectively, boosting the input line voltage tothe higher level needed to fully charge or equalize the batteries.

Referring now to FIG. 2 there is shown a more detailed schematic ofdrive system 10 of FIG. 1. FIG. 2 includes the previously describedcomponents of FIG. 1, namely, shore power connections 15A and 15B,generators 20A and 20B, AC bus 18 comprised of AC bus 18A and AC bus18B, rectifiers 25A and 25B, battery banks 30A and 30B, DC Bus 40comprised of DC bus 40A and a DC bus 40B, inverters 50A and 50B, 52, 54Aand 54B, 56A and 56B, motor control centers 60A and 60B, winch motor 62,steering motors 64A and 64B, thruster motors 66A and 66B, choppers 58Aand 58B, grid resistors 68A and 68B, and fire pump motors 72A and 72B.Furthermore, there is shown a diesel engine 10A that drives generator20A and a diesel engine 10B that drives generator 20B.

The engine and generator controls are uniquely designed to vary the ACvoltage and the frequency as the DC bus is not adversely affected bythese changes. This operating system allows for greater utilization ofthe power input from the engine generator sets by allowing the engine toramp down the RPM in low power applications as the power system is notsolely dependant upon fixed frequency or fixed voltage.

The generator excitation output is strictly controlled and allows forthe generator output voltage to be increased or decreased as needed forrapid charging rates and battery output current regulation at differentrates of charge.

The engine RPM is strictly controlled and allows for the engine RPM tofluctuate, and thus the generator output frequency to vary resulting inmaximizing the efficiency of the diesel engine when loads are beneaththe 80% threshold of operation.

Referring now to FIGS. 1 and 2, battery banks 30A and 30B are similarunits, each bank consisting of 320 individual 2-volt batteries connectedin series. The batteries are connected together via copper busconnections. The rated supply voltage for output is 320×2 VDC=640 VDC.The cells are rated for 3250 ADC of short time current flow.

Each individual battery weighs 268 lbs. The total weight of each batterybank 30A and 30B is approximately 85,760 lbs with an additional 865 lbsfor the battery mounting support system.

Batteries that may be used in battery banks 30A and 30B in accordancewith the present invention are batteries manufactured by EnerSys, modelDDm127-27, rated 1625 ah for MHS. Other similar batteries may be used toform battery banks 30A and 30B.

Battery banks 30A and 30B are suitably connected to be charged bygenerators 20A and 20B, respectively. Bypasses are also provided to havebattery bank 30A charged by generator 20B and battery bank 30B chargedby generator 20A. During operation on battery power, if the batterycharge drops below a preset level, diesel engines 10A and 10Bautomatically start and provide power to the battery charging system.Further, appropriate connections are provided to connect to and chargebattery banks 30A and 30B by dockside power sources through shore powerconnections 15A and 15B when the vessel is at the dock.

Battery banks 30A and 30B are suitably designed to be charged in bothfloat and fast charge methods from shore power or via the generatorswhile underway.

Referring now to FIG. 2, a charging system 92A is connected to AC bus18A to receive current for charging battery bank 30A and a chargingsystem 92B is connected to AC bus 18B to receive current for chargingbattery bank 30B. Charging systems 92A and 92B are inactive when thedrive power is provided to the tugboat only by battery banks 30A and30B. Generators 20A and 20B are configured to charge battery banks 30Aand 30B or provide additional power as needed, as described below. Whenthe PMS determines battery bank 30A or 30B has crossed the presetthreshold of charge, generator 20A or generator 20B is started andbrought online. After the completion of a bus 40A or bus 40B activefront end to supply power to the corresponding DC bus and relieve thecurrent load from the corresponding battery bank 30A or 30B has beenconfirmed, charging system 92A or 92Ber is connected to battery bank 30Aor 30B, respectively, and begins the charging process.

The charging system for each battery bank 30A or 30B is broken intothree (3) separate charging groups, each group being charged at a time.When the propulsion system is active, the battery charging system isrotated between the groups at intervals of 45 minutes each.

The charging requirement for the battery type is based upon voltage percell (constant voltage). For a 2-volt cell, the trickle charge rate percell is 2.16 VDC and the rapid charge rate is 2.34 VDC

The hardware for charging the batteries is an AC inverter with theability to transfer current bi directional. Alternately, a full wavediode bridge is used with charging currents regulated by variance of theboth the generator voltage output and the engine RPM. As the vessel'sservice loads are supplied power through an AC inverter assembly, thesevariations do not affect the vessel's service loads.

Still referring to FIG. 2, battery monitors 96A and 96B monitor batterybanks 30A and 30B, respectively. Battery banks 30A and 30B are monitoredby incorporating voltage sensors that provide a scaled analog voltagefeedback of the monitored batteries when the voltage is reduced belowpreset levels. The monitoring system uses the prescribed method asprovided by the battery manufacturer to determine the lowest battery ineach individual battery bank. Battery monitors 96A and 96B identifypotential problems early by tracking the voltage and temperature of eachcell.

Battery monitors 96A and 96B consist of cell monitors that measure thevoltage and temperature of individual battery cells, and a master unitthat reads the cell monitors and communicates with the system controllerover Profibus communications. The master unit also reads the full cellvoltage, battery current sensors, and local ambient temperature. Analgorithm of the data may be run to determine the condition of batterybank 30A and 30B and to place limits upon the current draw allowed.

Although the system may be operated by monitoring any number of cellsfrom 1 to 320, it is mostly preferred that all 320 cells on each ofbattery banks 30A and 30B be monitored individually. In the mostpreferred mode of the present invention, every cell is monitored anddata for every cell can be used to optimize battery performance andlife. Each battery monitor reads the cell voltage and local temperature,digitizes and galvanically isolates the data, and connects to a daisychained serial data network.

No individual battery cell shall be allowed depletion past 60%, thusextending the maximum power of the system delivery to the propulsionunits. If a battery draws down to or below the 60% level, generator 20Aor 20B assigned to that bus starts automatically, closes onto the mainbus and relieves the current draw from the battery bank and providescharging current to the battery bank at the same time interval. Thebattery bank charge levels are indicated on the HMI displays located inthe drive space and the pilot control.

Drive system 10 is built around battery banks 30A and 30B that serve asthe backbone of the system. The selection of the battery operatingvoltage drives the selection of the motors, generators, and drivemodules. A typical operating voltage is based upon a 480 volt systemOther systems, however, with lower or higher voltages may be used inaccordance with the present invention. If the loads and sources are notselected to be directly compatible with the battery voltage, thenadditional power conversion will be required, imposing cost, size andefficiency penalties. Therefore, system design is based upon the loadsand coordinated with the battery supply to formulate a coordinatedoperating system that is both cost effective and workable.

The following is the load voltage calculation for the 480 VAC system.The nominal battery voltage is 640 volts DC (2.0 V*320 cells). Theminimum DC voltage needed to make AC voltage is the rms voltage timesthe square root of two:

480 VAC*1.414=>679 VDC

440 VAC*1.414=>622 VDC

With 640 volts input a suitably designed electronic inverter cansynthesize high quality 440 volt AC power, or distorted 480 volt power.Therefore the load motors and motor control center should be specifiedat 440 VAC.

The following is the line voltage calculation. The battery chargingvoltage is 690 volts(2.16 V/cell), rising to a maximum of 750 VDC (2.34V/cell) under fast charge conditions. Rectified three phase power underload provides a voltage equal to 1.35 times the rms AC voltage. Underlight load conditions the DC voltage peak charges to 1.414 times the ACvoltage:

480 VAC*1.35=>648 VDC

480 VAC*1.414=>679 VDC

By these calculations, it can be seen that under load a 480 volt sourcewill closely match the nominal battery voltage, and under light loadwill approach the normal charging voltage. In order to provide thespecified fast charge voltage the AC voltage would need to be increased:

750 VDC/1.35=>555 VAC under load

750 VDC/1.414=>530 VAC at light load for finishing charge

This level of boost is readily provided by inverters 50A and 50B runwith reverse power flow, so that those inverters can serve double dutyas battery chargers when operating from shore power through shore powerconnections 15A and 15B.

Diesel engines 10A and 10B are similar units, each having a minimum KWrating of 1800 KW. Diesel engines 10A and 10B are suitably designed tomeet and/or exceed EPA Tier 2 emissions throughout the range of loadedconditions. Diesel engines 10A and 10B are suitably rated to marine useas stipulated by the American Bureau of Shipping (“ABS”) requirementsand suitably designed to utilize marine heat exchangers for the primarymethod of cooling. Diesel fuel requirement is standard and thus, dieselengines 10A and 10B can be fueled at any standard supplier of dieselfuels along the coastal waterways.

Diesel engines 10A and 10B have local engine monitoring functionscomplete with electronic capability to communicate with the vessel PowerManagement System (“PMS”) via serial connection.

Diesel engines 10A and 10B provide mechanical power to rotate generators20A and 20B, respectively, at a set speed. Generators 20A and 20Bconvert the mechanical energy into electrical energy usable by thevessels systems.

Generators 20A and 20B which are similar units are suitable designed for460-690 VAC, 2500 kVA, 45-60 Hz electrical requirements. They havewinding and bearing temperature monitoring devices to satisfy AmericanBureau of Shipping (“ABS”) marine propulsion power system requirement.These devices are 100 ohm platinum RTD's.

Any commercially available diesel engines and generators meeting thestated specifications may be used as diesel engines 10A and 10B andgenerators 20A and 20B. A preferred diesel engine/generator package isthe Marine Caterpillar Model 3516B DITA Direct Injection Turbochargedwhich is after cooled with a separate circuit after cooling. Thepreferred generator 20A and 20B is a Kato or equivalent 480 VAC, 60 Hzgenerator. This offshore electric diesel engine/generator with a ratingof 1825 KW @ 1800 RPM includes the following standard attachments:

Air Inlet System (after cooler core (corrosion resistant), air cleaner(regular duty with soot filter), service indicators)

Control System (Caterpillar ADEM II Electronic Engine Control (lefthand), requires 24V DC 10 Amp continuous, 20 AMP intermittent, cleanelectrical power).

Heat Exchanger Cooled Marine (Outlet controlled thermostat and housing,jacket water pump gear driven, single outlet with tubed heat exchanger,gear driven centrifugal after cooler fresh water cooling pump (SCAC),SCAC pump circuit contains a thermostat to keep the after cooler coolantfrom falling below 30 deg C. (85 F)).

Exhaust System (standard stroke exhaust fittings (flexible 203 mm (8in)), standard stroke exhaust flange (weldable 356 mm (14 in), dry gastight exhaust manifolds with thermo-laminated heat shields, dualturbochargers and thermo-laminated heat shields).

Flywheels and Flywheel Housings (flywheel (SAE No. 00 with 183 teeth),flywheel housing (SAE No. 00), SAE standard rotation).

Fuel System (fuel filter (left hand), fuel transfer pump, flexible fuellines, fuel priming pump (left hand), electronically controlled unitinjectors).

Instrumentation (electronic instrument panel (left hand); analog gaugeswith digital display data for engine oil pressure gauge, engine watertemperature gauge, fuel pressure gauge, system DC voltage gauge, airinlet restriction gauge, exhaust temperature (prior to turbochargers)gauge, fuel filter differential pressure gauge, oil filter differentialpressure gauge, service meter (digital display only), tachometer(digital display only), instantaneous fuel consumption (digital displayonly), total fuel consumed (digital display only), and engine start-stop(off, auto start, manual start, cool down timer))

Lube System (crankcase breather, oil cooler, oil filter(left hand), deepoil pan, oil pan drain valve(2″ NPT female connection), lubricating oil(SAE 10W30, Caterpillar DEO (CG4) 813 L)).

Mounting System (rails, mounting, floor type, 254 mm (10 in)).

Power Take-offs (accessory drives, upper right hand, lower left handFront (available for PTO usage), front housing (two-sided)).

Starting System (air pre lube pump, air starting motor (right hand, 620to 1034 kPa (90 to 150 psi), left hand control), air silencer).

General (paint (caterpillar yellow), vibration damper and guard, liftingeyes).

Fuel Cooler. One Young Touchstone Remote vertical fuel cooler withhorizontal discharge is installed. Radiator is sized to cool up to five3516B engines manifolded together or standard marine heat exchangers maybe used as room permits. It Includes Heresite coated core and hot dippedgalvanized steel parts, 5 HP TEXP motor (3 ph/230/460 volt) and core andfan guards.

Protection System. ADEM II or any other equivalent monitoring systemprovides engine de-ration, alarm, or shutdown strategies to protectagainst adverse operating conditions. Selected parameters are customerprogrammable. Status available on engine mounted instrument panel andcan be broadcast through the optional customer communications module orprogrammable relay control modules(s)). Initially it is set as follows:

Safety Shutoff Protection, Electrical (oil pressure, water temperature,overspeed, crankcase pressure, after cooler temperature; includes airinlet shutoff, activated on overspend or emergency stop).

Alarms, Electrical (ECM voltage, oil pressure, water temperature (lowand high), overspend, crankcase pressure, after cooler temperature lowwater level (sensor is optional attachment), air inlet restriction,exhaust stack temperature, filter differential pressure (oil and fuel)).

Derate, electrical (high water temperature, crankcase pressure, aftercooler temperature, air inlet restriction, altitude, exhausttemperature; emergency stop push button, located on instrument panel;alarm switches (oil pressure and water temperature), for connection toalarm panel).

Each diesel engine 10A/generator 20A and diesel engine 10A/generator 20Bset includes a control cubicle for load sharing control. Each controlcubicle includes the following:

3200 amp rack out main breaker with LSI adjustable trip, under voltagetrip and trip indicator; 3×4500:5 current transformers; 1 RHCC loadsharing speed control unit for active KW and KVAR load sharing controlof the engine and generator set (controller includes protections forunder voltage, over voltage, over frequency, under frequency and reversepower; AC module control transformer; sync control transformer and AutoSync controls; excitation power transformer; engine OFF/IDLE/RUN switch;generator sync selector switch; interlocked breaker close push button;digital screen display power management meter (Siemens 9500) for displayof 3 phase voltage, 3 phase amperage, frequency, Kilowatts, Kilovars,bus harmonics and voltage fluctuation and record trending of up to 3years accumulative engine/generator load and fault data; RTD generatortemperature display for winding 1, winding 2, winding 3, drive bearingand tail bearing; power limit interface with AC drives and batterydemand monitor; hour meter indicating hours online; generator run light;generator online light; emergency shutdown interface relay; generatorheater relay; no touch control fuses; marine non conductive handrails;marine drip shield IP20; engine/generator field connection terminalblock; AC Bus ground fault indication

Still referring to FIGS. 1 and 2, each of inverters 50A, 50B, 52, 54A,54B, 56A and 56 B and choppers 58A and 58B consist of a plurality ofmodules, preferably, TeraTorq Inverter Modules (TIM-200). Each modulecan drive 300 HP and can be configured in real-time for a number ofdifferent modes of operation. The TIM-200 modules are 28 inches deep 6inches wide and 13 inches high. All of the high power connections areblind-mate connectors in the back so the modules can be replaced withouthandling dangerous bus voltages. A TIM-200 module has blind mate powerconnections, AC & DC fuses, IGBT switches, 32 Bit DSP controls andliquid cooling connections. Blind mate power connections are suitablefor removing and replacing a particular module without touching thepower conductors. AC & DC fuses are included in every power lead wherebyany problem that may occur in a particular module is isolated in theparticular module without affecting the other modules. The IGBT switchesare 1700 volt switches that provide sufficient margin for unexpectedevents. The 32 bit DSP controls is a built in 32 bit 150 MHz digitalsignal processor that enables a particular module to respond instantlyand correctly to changing voltages, currents and temperatures. Liquidcooling connections provide for the flow of high performance heat sinkliquid that removes heat form the IGBT switches of the module. Eachmodule has digital status readout.

A plurality of modules is inserted in a cabinet with the cooling and CANbus connections allowing for the easy access, removal and insertion ofeach module.

Still referring to FIGS. 1 and 2, each of inverters 50A and 50B has 2TIM-200 drive modules (4 modules total) and provide 60 Hz 440 VAC powerfor distribution through a motor control center. The power is 250 kW andthe current is 400 A. Inverters 50A and 50B are also back driven toprovide DC power for battery charging when on shore power.

Inverter 52 has 1 TIM-200 module and provides four-quadrant variablespeed control to a 150 kW induction motor, voltage 440 VAC and current200 A. Other inverters may be used as long as special modifications aremade to the firmware to ensure that the DC bus voltage can be operatedat a large differential (200 vdc-1000 vdc) without faulting.

Each of inverters 54A and 54B has 1 TIM-200 module (2 modules total) andprovides four-quadrant variable speed control to induction motorstotaling 100 kW, current 150 A and 440 VAC.

Still referring to FIGS. 1 and 2, inverters 54A and 54B have 15 TIM-200modules each. They each provide four-quadrant variable speed control toa 2500 kW induction motor, current 3000 A, 440 VAC.

Each of choppers 58A and 58B (600 kW, 800 A, 750 VDC, 2 TIM-200 moduleseach) handle excess electric power from the thrusters and winch whenthey regenerate power. Each of choppers 58A and 58B sends any unusableelectric power to external load resistors 68A and 68B, respectively, tobe dissipated.

Drive system 10 includes two drive cabinets (one for the port sectionand the other for the starboard section). Drive cabinet contains thecoolant, control, and power connections for the system. It is arrangedas a grid, with each the modules for each subsystem typically installedside by side on a single row, or multiple rows for higher power devices.Each of the two cabinets requires 55 gallons per minute of liquidcoolant (110 GPM total).

Referring now to FIG. 1, AC bus 18A and AC bus 18B is assembled as asingular bus system and it supplies power to battery charging systems92A and 92B, fire pump motors 72A and 72 b and the charging systems ofDC Bus 18A and DC bus 18B.

All power breakers connected to AC bus 18A and AC bus 18B have thecapability for remote closure and remote disconnect. The status of thebreaker is also monitored by the PMS automation and provides operatingstatus and interlock functionality.

The main bus and marine switchgear is designed with the followingstandards: main bus rating of 5500 amps for ac bus distribution; busfault rating is 100 KIA @ 480 VAC; main bus is plated copper; main bushardware is stainless grade 8 hardware Switchgear construction is weldedsteel frame with 12 gauge hinged doors; all cubicles requiring forcedair ventilation have louvered vents with filtered suction; all breakersare rack out marine type as per requirement; all breakers have Profibuscommunications capability; all breakers with ratings greater than 600amps supplied with auto charging controls for stored energy devices andremoter close solenoids; shore power breaker is interlocked with thegenerator breakers; status of main bus and interlock condition isindicated by visual indicator (light); all breaker nomenclature toinclude breaker setting information, load or source information andcomponent reference id; local and remote ground fault indications; nonconductive hand rails as per abs requirement; drip shields as per ABSrequirement; paint requirement is ASA 61 Polane B or equivalent coatingsystem; 15′ color touch screen centrally located in the switchgear forease of monitoring system status and/or alarm conditions; generatortemperature rtds are tied into pms alarm system with set points as permanufacture specifications; engine-generator control system hasauto/off/manual mode selection for maintenance purposes; fire pumpcontrols to include soft start system to reduce magnetizing currentthroughput when starting motors. Soft starters are complete with bypasscontactors; and all status indication lights located on front doors are24 volt with exception of generator status lights on generator controlcubicle doors.

Still referring to FIG. 1, circuit breakers 76A and 76B are SiemensWL1000AF, rack out marine use (or equivalent); 600 A rating plug, LSIelectronic trip unit; 120 VAC motor charging unit; 120 VAC remote closecoil; 120 VAC under voltage trip unit, Profi Bus communications option;3 sets NO contacts; 3 sets NC contacts. Circuit breakers 78A and 78B areSiemens WL3200AF, rack out marine use (or equivalent); 3200 A ratingplug, LSI adjustable electronic trip unit; 120 VAC motor charging unit;120 VAC remote close coil; 120 VAC under voltage trip unit, Profi Buscommunications option; 3 sets NO contacts; 3 sets NC contacts.

Circuit breakers 82A and 82B are Siemens WL1600AF, rack out marine use(or equivalent); 1600 A rating plug, LSI adjustable electronic tripunit; 120 VAC motor charging unit; 120 VAC remote close coil; 120 VACunder voltage trip unit, Profi Bus communications option; 3 sets NOcontacts; 3 sets NC contacts.

Circuit breakers 84A and 84B are Siemens WL3200AF, rack out marine use(or equivalent); 2500 A rating plug, LSI adjustable electronic tripunit; 120 VAC motor charging unit; 120 VAC remote close coil; 120 VACunder voltage trip unit, Profi Bus communications option; 3 sets NOcontacts; 3 sets NC contacts.

Referring now to FIG. 2, breakers 98A and 98 b for charging systems 92Aand 92B are shown. Breakers 98A and 98B are Siemens WL1000AF, rack outmarine use (or equivalent); 1000 A rating plug, LSI adjustableelectronic trip unit; 120 VAC motor charging unit; 120 VAC remote closecoil; 120 VAC under voltage trip unit, Profi Bus communications option;3 sets NO contacts; 3 sets NC contacts.

Referring now to FIG. 3, there is shown system control 100 forcontrolling and monitoring drive system 10. Control system 100 iscomprised of two redundant systems, a pilot house controller 102 and adrive space controller 104. Both pilot house controller 102 and drivespace controller 104 are capable of complete system control andmonitoring independent of each other. Each of pilot house controller 102and drive space controller 104 has a system control software thatresides in a National Instruments PXI-1042 chassis with a real timeoperating system.

The controller chassis is configured with dual independent profibus 106Aand 106B that provide separate control of the port and starboardcommunication networks, respectively. Profibus 106A is the conduit ofcommands and data with local subsystems in the port communicationsnetwork including a controller 108A for generator 20A, a monitor 110Afor battery bank 30A, a controller 112A for a subsystem 113A forinverters 50A, 52, 54A and chopper 58A, a controller 114A for asubsystem 115A for inverter 56A, a circuit breaker 116A, a motor starter118A, a circuit breaker 120A and a motor starter 122A. Some of thesubsystems are simple monitors that only report data (for example thebattery voltage monitors and circuit breaker status monitors). Othersubsystems receive and execute commands as well as reporting data (forexample the motor controllers and the generator controls). The inverterdrive subsystems have an additional level of control network. Commandsand data are exchanged with the system controller over Profibus, and thelocal controller coordinates the operation of inverter modules using aCAN bus.

Similarly, profibus 106B is the conduit of commands and data with localsubsystems in the starboard communications network including acontroller 108B for generator 20B, a monitor 110B for battery bank 30B,a controller 112B for a subsystem 113B for inverters 50B, 54B andchopper 58B, a controller 114B for a subsystem 115B for inverter 56B, acircuit breaker 116B, a motor starter 118B, a circuit breaker 120B and amotor starter 122B. Like in the port network, some of the subsystems ofthe starboard network are simple monitors that only report data (forexample the battery voltage monitors and circuit breaker statusmonitors). Other subsystems receive and execute commands as well asreporting data (for example the motor controllers and the generatorcontrols). The inverter drive subsystems have an additional level ofcontrol network. Commands and data are exchanged with the systemcontroller over Profibus, and the local controller coordinates theoperation of inverter modules using a CAN bus.

Control system 100 provides reliable and responsive operation of all ofthe elements of the power system through a simple and redundant operatorinterface. Primary control is performed from the pilot house where pilothouse controller 102 is controller using pilot house manual controls130, such as switches, knobs, levers, and joysticks, at the left edge ofthe diagram. Clear visual feedback of propeller speed can be provided ontwo dial gauges. Pilot house manual controls 130 are supplemented by atouch screen computer display 132. Touch screen computer display 132provides detailed operating status information. A graphical userinterface lets the operator select the data to be displayed, changeoperating modes and limits, and acknowledge status messages. Theunderlying philosophy is that time-critical and frequently used controlshave dedicated manual inputs, and the rest are accessed through thetouch screen.

Pilot house manual controls 130 and pilot house touch screen monitor 132are connected to pilot house control 102, which is a modular controllerchassis running a real time operating system. This unit contains thecontrol and interlock programming that coordinates system operation. Itcommunicates with the power system components over the two separateprofibus networks profibus 106A and 106B.

The redundant set of controls drive space 104 is located in the drivespace of the vessel and is connected to drive space manual controls 140similar to pilot house manual control 130 and drive space touch screenmonitor 142 similar to pilot house touch screen monitor 132. Drive spacecontroller 104 provides local monitoring and display of system status,but only exerts control if assigned by the pilot house or if pilot housecontroller 102 is offline. This architecture provides a high degree ofprotection because each of the independent communication networks can beindependently controlled by two physically separate control stations.

In a typical configuration, the control system and hardwareconfiguration has the safety features designed into the system. Thesafety functions are broken into specific hardware and/or operatingfunction groups. Examples of such safety functions include thefollowing:

SAFETY FUNCTION ACTION Reverse Power Trip Breaker-Engine Shut down OverSpeed Trip Breaker-Engine Shut down Under Voltage Trip Breaker OverVoltage Trip Breaker Generator Over Temp Alarm Synchronization CheckBreaker Closure Control Permissive Ground Fault Alarm DC Bus 40A FaultAlarm - Shutdown DC Bus 40B Fault Alarm - Shutdown Charging Unit 92AFault Alarm - Reduction output Battery Bank 30A Charging Unit 92bB FaultAlarm - Reduction output Battery Bank B Propulsion Motor OvertempAlarm - Shut Propulsion Motor

The control system and hardware configuration of drive system 10 hasseveral interlock functions suitable for the operation of drive system10. Such interlock functions include the following:

-   -   Shore Power Breaker interlocked with Energized Bus Sensor. Shore        Power Breaker cannot be closed with AC Bus 18 energized or        Generator 20A or Generator 20B breaker closed.    -   Battery Banks 20A and 20B—Tie manual DC contactor switches.        Logic statement is as follows;    -   A=1, B=1, T=0    -   A=0, B=1, T=0 OR 1    -   A=1, B=0, T=0 OR 1    -   Fire Pumps Disabled unless FIRE FIGHTING Mode selected.    -   Main Propulsion Drives not enabled unless permissive received        from aux function enable circuit (Shottel System or Equivalent).    -   AC/DC Converters 25A & 25B cannot be enabled if DC Bus 40 fault        exists.    -   Port MCC drive feed interlocked with backup 480 VAC Bus feed        breaker. Normal operation is from AC drive inverter supply. Back        emergency failure mode is fed from 480-volt bus.    -   Starboard MCC drive feed interlocked with backup 480 VAC Bus        feed breaker. Normal operation is from AC drive inverter supply.        Back emergency failure mode is fed from 480-volt bus.

Drive system 10 and the vessel utilizing drive system 10 areappropriately designed to operate in three different modes, namely, thegreen mode, the tow mode and the firefighting mode. Green mode is thedefault mode of operation. The operator can select either tow mode orfirefighting mode to override some of the automatic power managementfunctions of the control system.

In the green mode the vessel is supplied power only by the batteries inbattery banks 30A and 30B without utilizing the diesel engines for shippropulsion and/or ship service. Control system 100 energizes dieselengines 10A and 10B and generators only when needed to provide peakpower or battery charging. The batteries in battery banks 30A and 30Bhold enough energy to sustain 300 Hp of incidental loads for over 8hours between charges; however battery life is increased if more shallowdischarge cycles are used. Generators 20A and 20B come on lineautomatically based on a combination of the load and the battery stateof charge. In the green mode, the minimal use of diesel engines causesubstantial reduction in noise level, energy consumption and carbonemissions. Green mode is designed for operating the tugboat betweenlocations when it is not towing another vessel and for docksideoperations.

The tow mode may be manually selected by the operator. Selecting towmode energizes diesel engines 10A and 10B and generators 20A and 20B sothat they will be available immediately to support peak power demands.The voltage from generators 20A and 20B maintains a float charge onbattery banks 30A and 30B except at very heavy loads, where power isdrawn from battery banks 30A and 30B to supplement generators 20A and20B.

The fire fighting mode may be manually selected by the operator.Firefighting mode energizes both diesel engines 10A and 10B andgenerators 20A and 20B, and gives priority to the fire pumps that aredriven by fire pump motors 72A and 72B. The power available tononessential systems is limited in this mode. The fire pumps receive ACpower directly from generators 20A and 20B, and are not dependent onbattery banks 30A and 30B or power conversion electronics.

The drive system operating modes differ in the sources of power and thepath that the power takes to the load. Each of the vessel operatingmodes may include several different drive operating modes. In normaloperation the control system automatically selects the drive systemoperating mode; however in some cases the operator may directly selectthe operating mode for maintenance or emergency conditions. For example,the maintenance schedule might call for battery equalization to be runonce every six months. The port and starboard sides of the drive systemmay be in the same or different modes at any time.

If the vessel is in green mode, there is sufficient charge in batterybanks 30A and 30 b, and the load is not too heavy, the drive system willrun on battery power. At no load and full charge the battery voltagewill be 675 volts DC. At 500 Horsepower total load the voltage will showa relatively modest droop to 660 volts. The system could be run underthis condition for over five hours from fully charged batteries; howeverstarting diesel engines 10A and 10B and generators 20A and 20Bperiodically will increase the service life of battery banks 30A and 30Bby removing load (current draw) from battery banks 30A and 30B andproviding charging current, which will be proportional to the overallsystem load.

An analysis determines the optimal generator starting scenarios. Forexample, at 90% state of charge the diesels might be programmed to comeon at a load equal to 25% of the one-hour discharge current, and 10%current at 75% state of charge. The goal of the optimization is tominimize pollution and fuel use, while maximizing service life.

When operating from battery power there is no voltage on the AC bus 18coming in to rectifiers 25A and 25B. All AC power for the MCCs and motorloads is synthesized from battery voltage from DC Bus 40A and DC bus 40Bby the inverters. The battery state of charge is calculated by measuringthe battery cell voltage, temperature, and load current using networkedintegrated circuit boards attached to the batteries.

When generators 20A and 20B are brought on line they feed AC power torectifiers 25A and 25B, which in turn provide DC power to battery banks30A and 30B and inverters. If the AC voltage is low the rectifier outputwill be too low to feed power into DC bus 40, and the system willcontinue to run from battery power. As the AC voltage is increased, therectifier will start to take load off of the batteries, causing thebattery terminal voltage to increase. If the AC voltage is increasedfurther, the rectifier will provide all of the load current to theinverters and will also provide current to recharge the batteries. Thepower output of the generators and the charging rate of the batteriescan be controlled by varying the generator voltage over a fairly narrowrange. This concept is unique in that the excitation level is varied dueto the charging rate needed for the battery bank. The excitation haslimits placed upon it so not to exceed the maximum limits of the DC busattached to the AC drive units.

Good control of the DC bus voltage is essential for maximum batterylife. The applied charging voltage must be adjusted for batteryoperating temperature, and the charging current must be limited to avoidexcess heating. Also, over-charging must be avoided because it can leadto gas discharge or thermal runaway. For this reason, it is veryimportant that the generator voltage be automatically adjusted by theautomated power control system.

As in battery power mode, when generators 20A and 20 b are on, all ACvoltages for the MCCs and motor loads are synthesized from DC voltage bythe inverters. However, AC power from generators 20A and 20B isavailable to the fire pumps connected directly to the 480 volt Bus inthis mode. Generators 20A and 20B can be run separately to regulatebattery banks 30A and 30B independently, or the AC bus 40A and AC bus40B can be cross connected to charge both battery banks from a singlegenerator or a pair of synchronized generators. When operating in thismode the generator VAR sharing circuits are synchronized to providecurrent from the same amplitude of current from each generator.

When the vessel is connected to 480 volt shore power via shore powerconnections 15A and 15B, battery banks 30A and 30B can be charged andloads can be run without powering generators 20A and 20B. The preferredconnection for shore power is directly into the port and starboard MCCs.With this configuration MCC loads can be run even if the driveelectronics or batteries are disabled for maintenance.

Battery charge regulation is provided by inverters 50A and 50B thatnormally synthesize MCC power from the battery voltage. They operate asboost rectifiers to provide the proper charging voltage for batterybanks 30A and 30B. At room temperature the battery voltage is regulatedto 690 volts to maintain a float charge, or 750 volts for a fast chargeor charge equalization. At higher temperature the voltages is reduced.

Shore power can also be connected to AC bus 18 at the generators. Thisallows the fire pumps to be operated, and allows charging of batterybanks 30A and 30B through rectifiers 25A and 25B. It should be noted,however, that only a low level of charge is possible through this pathunless the incoming voltage exceeds 480 volts.

A variety of maintenance modes are available to deal with unusualsituations. For example, bypass circuits allow the MCCs to be connecteddirectly to the output of generators 20A and 20B, or allow the firepumps to operate from the MCCs. Both battery banks 30A and 30B can becharged from a single generator 20A or 20B. The port and starboardinverters can be cross connected to operate from a single battery bank30A or 30B. By providing such designs, when a failure occurs in thesystem, such failure causes only a partial and not a total disablementof the vessel thereby allowing the vessel to operate.

The use of the combination of battery banks 30A and 30B and generators20A and 20B allows for reduction of use of generators 20A and 20B incertain operating modes and, more particularly, in the green mode. Thebattery output from battery banks 30A and 30B is connected to DC bus 40that provides power to the AC drives which are electronically controlledand provide power to the thrusters and all ships service. The tugboathas the ability to be mobilized without the need to operate generators20A and 20B and can operate for prolonged periods on battery poweralone. Generators 20A and 20B are only used in the towing mode, firefighting mode or when charging the batteries. As a result, fuelconsumption is reduced thereby reducing fuel costs and carbon emissionsfrom the vessel. It is estimated that carbon emissions are reduced by asmuch as 90 percent as compared to the previous designs of tugboats andoperations.

In drive system 10, power may be drawn from generators 20A and 20B,shore power connections 15A and 15B, or battery banks 30A and 30B. Powermay be drawn by large loads, such as the thrusters, steering, winch, andbattery, or by smaller loads attached to the motor control centers.System efficiency is maximized by streamlining the paths among the loadsand sources, and by ensuring seamless transitions as conditions change.

The control system of drive system 10 is configured to draw energy fromthe most efficient source. In addition the system supports re-generationto channel energy from the drive back into battery banks 30A and 30Bunder certain conditions as previously described.

The replacement of diesel engines and generators with battery banks 30Aand 30B reduces the size of the drive line and the overall spacerequired for it. It is estimated that the space is about 50% smallerthan that required for other commercial drives.

The use of a set of identical modules TIM-200 allows for theirreplacement at sea without an electrician and results in reduction ofdown time and maintenance costs. Modules TIM-200 are automaticallyre-programmed for the specific application and can be swapped at sea.For example, the winch drive requires a single module while eachthruster uses 15 modules. If a winch drive module fails, it can bereplaced by one of the thruster modules and while the maximum thrusterpower would be limited slightly, the winch would be fully operational.

Drive system 10 is designed to comply with the design and manufacturespecifications of the American Bureau of Shipping as found in the Rulesfor Steel Vessels 2007, and subsequent amended documents with regard toABS manufacturing rules for steel vessels of this class with specialemphasis on redundancy and emergency mode requirements referred to inPart 4 Chapter 8.

The system is controlled by standard software that are available withthe components of the system. The software is suitably programmed tocontrol the operation as described herein.

The operating system design of the marine hybrid propulsion systemallows for the vessel to make way without the need to operate any dieselengines. This is considered unique as no other system has this ability.The unique design features are described below.

The control system allows for vessel to be under way without the needfor diesel engine power source to be online. This is unique to thevessel operating system from all other propulsion control systems. Theresult is a dramatic fuel reduction usage due to the requirement that noprime movers are needed for propulsion and ships service power, carbonemissions are inherently reduced for the same reason plus a dramaticreduction in baseline ambient noise of the vessel in operations. Allthree of these areas are beneficial to harbor operations for tug boatsand ferries.

Battery system charge can be refreshed rapidly by precise control ofengine (prime mover) RPM and generator voltage output (due to thevariable excitation control system) without affecting the power outputcontrol capability of the propulsion system or the vessel servicesupplies. During rapid refresh the needed power output from thecontrolled power output devices are constant and consistent with thepower needed for any specific purpose.

In any mode of operations, the vessel hull inertial stored energy can beharvested with reduction of vessel speed commands and returned to theenergy storage system (battery banks) by the automated electroniccontrol system or the energy can be placed into the vessel ships servicesystem. This maximizes overall power system efficiency by harvestingships hull inertial energy and subsequent conversion to a usable sourceenergy.

Power is supplied to the vessel by one of three most efficient sourcesas defined by the vessel's automated vessel power management system. Thethree (3) sources of power are:

-   -   (a) Stored energy battery supply power source, which depending        upon the system design is between 1.5 mega watt to 10 megawatts;    -   (b) Diesel engine generator power source; and    -   (c) Shore power source when connected dockside.

In the latter case, the stored energy charging system and the vessel'sservice power used are transferred to the most efficient source which islocated at the power generation plant. Typically power generation plantsare regulated thereby limiting the total amount of carbon emissionsallowed per kilowatt hour of power generated.

Battery storage and power delivery system is managed on a per cell andper group basis. This allows for very efficient power management intoand out of the battery stored energy system.

The vessel control system is designed with a green mode of vesseloperations unique to the system operating system design. As previouslystated, this allows the vessel to make way (propulsion systems and shipsservice systems active) without the need to have diesel enginesoperating, resulting in reduced carbon fuel consumption and theresultant reduced carbon emissions. The green mode of operations alsoallows for reduced sound decibel levels during operations, whichbenefits local populations and the personnel operating the vesselonboard. The power draw from the stored energy system is electronicallymonitored and controlled by the unique control system design in thefollowing method and results:

-   -   (a) The stored energy is calculated and the energy drawdown is        electronically controlled based upon the total available energy        calculation of the stored energy battery system;    -   (b) The AC propulsion drive current limits are continuously        monitored and adjusted and so the propulsion system efficiency        is considered during operation to maximize total system        efficiency. This is seamless to the vessel operator and        comparable to the fly by wire operation of air craft and modern        automobiles.    -   (c) As stated above, by slowing the vessel down during green        mode the energy from the vessel is harvested by the permanent        magnetic propulsion motors and delivered back to the stored        energy system or to the ships service power system. Either way,        there is a reduction of energy draw from the stored energy        system thus maximizing efficiency of the overall power system.

Vessel automated power management allows for dramatic drop in DC busvoltage in emergency vessel operating conditions. These conditions aredefined as the vessel being underway and the use of diesel engine powergenerating plants are lost (for whatever reason, mechanical problems,loss of fuel supply, etc.). The AC drive operating algorithms allow fora wide range of DC bus fluctuations which allow for large draw down inpower from the energy storage battery banks in emergency operatingstates as defined. This is unique to the system operating design.

Sufficient warnings to the operator by the vessel control automationsystem are provided to alert the operator to adverse equipmentconditions. These include the cell by cell monitoring of the storedenergy system (batteries), therefore the operating system providesadvance notice of any potential adverse equipment condition. The batterycell monitor produces an alarm condition if the cells have adifferential voltage in excess of 1 volt DC. The battery monitoringsystem senses, displays and records the temperature of each individualbattery cell. The operating system is programmed to predict a cellfailure in advance.

While a preferred embodiment of the present invention has beenillustrated and described, various changes and modifications can be madeby one skilled in the art without departing from the spirit and scope ofthe invention and it is intended to cover in the appended claims allsuch changes and modifications that are within the scope of thisinvention.

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 23. A method of operating avessel, comprising: generating charging power from a generator thatprovides a voltage output; varying the voltage output of the generator;charging a battery system with the charging power; providing sufficientpower from the battery system to move the vessel; and moving the vessel.24. The method according to claim 23 wherein the step of moving thevessel includes the step of providing the power to a propeller of thevessel.
 25. The method according to claim 23 wherein the step ofgenerating charging power includes the step of utilizing power from agenerator.
 26. The method according to claim 23 wherein the step ofgenerating charging power includes the step of recovering energy fromthe vessel.
 27. The method according to claim 24 wherein the step ofgenerating charging power includes the step of recovering energy fromthe propeller of the vessel.
 28. The method according to claim 23further including the step of converting alternating current to directcurrent.
 29. The method according to claim 23 further including the stepof converting direct current to alternating current.
 30. The methodaccording to claim 23 further including the step of harvesting energyfrom the vessel.
 31. The method according to claim 23 further includingthe step of controlling the charging of the battery system.
 32. A methodof providing power to a vessel, comprising: generating charging powerfrom a generator that provides a voltage output; varying the voltageoutput of the generator; charging a battery system with the chargingpower; providing sufficient power from the battery system to satisfysubstantially all the power needs of the vessel.
 33. The methodaccording to claim 32 wherein the providing step includes the step ofsupplying all of the power needed to move the vessel.
 34. The methodaccording to claim 32 wherein the step of generating charging powerincludes the step of utilizing power from a generator.
 35. The methodaccording to claim 32 wherein the step of generating charging powerincludes the step of recovering energy from the vessel.
 36. The methodaccording to claim 33 wherein the step of generating charging powerincludes the step of recovering energy from the movement of the vessel.37. The method according to claim 32 further including the step ofconverting alternating current to direct current.
 38. The methodaccording to claim 32 further including the step of converting directcurrent to alternating current.
 39. The method according to claim 32further including the step of harvesting energy from the vessel.
 40. Themethod according to claim 32 further including the step of controllingthe charging of the battery system.
 41. The method according to claim 23further including the step of driving the generator by a diesel engine.42. The method according to claim 41 further including the step ofvarying the speed of the diesel engine.